Electronic structure tailoring of Al3+- and Ta5+-doped CeO2 for the synergistic removal of NO and chlorinated organics

Balancing the NH3 selective catalytic reduction (NH3-SCR) and catalytic oxidation performance is difficult but necessary for the synergistic elimination of NOx and chlorine-containing volatile organic compounds (CVOCs). We herein unveiled that electronic structure tailoring of the applied catalyst was an efficient pathway for balancing the catalytic behaviors in the NH3-SCR of NO and chlorobenzene catalytic oxidation (CBCO). Specifically, environmentally friendly CeO2 substituted by low valent Al3+ exhibited better NH3-SCR of NO and CBCO activity in comparison with the CeO2 sample without doping. Detailed characterizations and theoretical simulations revealed that the strong dopant-oxide pairs in the CeO2 with Al3+ doping significantly tailored the electronic structure of O 2p states, enhancing the amount of Lewis acid sites and promoting the ability of lattice oxygen to act as an oxidizing agent, thereby leading to superior performance for the synergistic elimination of NO/CB. The counterpart with substitution of high valent Ta5+ showed an opposite trend, due to that Ta5+ donated more electrons to the coordination oxygen than Ce4+ inhibiting lattice oxygen separating from the surface of the catalyst, and Lewis base sites were formed.